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/* trace.c - Tracing helper functions.
Copyright (C) 2008 Free Software Foundation, Inc.
Written by Neal H. Walfield <neal@gnu.org>.
This file is part of the GNU Hurd.
GNU Hurd is free software: you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.
GNU Hurd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with GNU Hurd. If not, see
<http://www.gnu.org/licenses/>. */
#ifndef _HURD_TRACE_H
#define _HURD_TRACE_H
#include <stdarg.h>
#include <assert.h>
#ifdef RM_INTERN
# include "../viengoos/mutex.h"
#else
# include <hurd/mutex.h>
#endif
#include <s-printf.h>
struct trace_buffer
{
/* A descriptive name for the trace buffer. */
char *name;
void *id;
bool nobacktrace;
bool notid;
bool nolock;
ss_mutex_t lock;
/* Number of bytes written to the buffer so far. */
int written;
/* Current offset in the buffer. */
int offset;
/* 2 pages. */
char buffer[2 * 4096];
/* A couple of local variables. This removes the necessity to
allocate them on the stack, which is a bit problematic as we'd
like to use this to debug exactly those cases where faulting on a
stack results in an exception. */
void *bt[20];
int count;
};
#define TRACE_BUFFER_INIT(name, id, save_backtrace, print_tid, do_lock) \
{ (name), (id), ! (save_backtrace), ! (print_tid), ! (do_lock) }
static inline void
trace_buffer_add (const char *func, const int lineno,
struct trace_buffer *buffer, char *fmt, ...)
{
int pc (int chr)
{
assert (buffer->offset < sizeof (buffer->buffer));
buffer->buffer[buffer->offset ++] = chr;
if (buffer->offset == sizeof (buffer->buffer))
buffer->offset = 0;
buffer->written ++;
return chr;
}
va_list ap;
if (! buffer->nolock)
ss_mutex_lock (&buffer->lock);
if (! buffer->notid)
s_cprintf (pc, "%x:", l4_myself ());
s_cprintf (pc, "%s:%d: ", func, lineno);
va_start (ap, fmt);
s_cvprintf (pc, fmt, ap);
va_end (ap);
/* Include a backtrace. */
if (! buffer->nobacktrace)
{
extern int backtrace (void **array, int size);
buffer->count = backtrace (buffer->bt,
(sizeof (buffer->bt)
/ sizeof (buffer->bt[0])));
int i;
pc (' '); pc ('(');
for (i = 0; i < buffer->count; i ++)
{
s_cprintf (pc, "%x", buffer->bt[i]);
if (i != buffer->count - 1)
pc (' ');
}
pc (')');
}
/* And add a terminating NUL. */
pc (0);
if (! buffer->nolock)
ss_mutex_unlock (&buffer->lock);
}
#define trace_buffer_add(buf, fmt, ...) \
trace_buffer_add (__FUNCTION__, __LINE__, buf, fmt, ##__VA_ARGS__)
static inline void
trace_buffer_dump (const char *func, int line,
struct trace_buffer *buffer, int count)
{
if (! buffer->nolock)
ss_mutex_lock (&buffer->lock);
s_printf ("%s:%d: Dumping trace buffer %s(%x)\n",
func, line, buffer->name, buffer->id);
if (buffer->written == 0)
{
s_puts ("Empty.\n");
if (! buffer->nolock)
ss_mutex_unlock (&buffer->lock);
return;
}
int record = 1;
int offset = buffer->offset - 1;
if (offset == -1)
offset = sizeof (buffer->buffer) - 1;
/* Number of bytes processed. (-1 as we increment for a byte that
we have not actually processed.) */
int processed = 0;
do
{
/* OFFSET is at the end of the next string. */
/* Last byte is a NUL character. */
assert (buffer->buffer[offset] == 0);
/* Find end of the preceding string. */
do
{
offset --, processed ++;
if (processed > sizeof (buffer->buffer))
{
if (! buffer->nolock)
ss_mutex_unlock (&buffer->lock);
return;
}
if (processed >= buffer->written)
break;
if (offset == -1)
offset = sizeof (buffer->buffer) - 1;
}
while (buffer->buffer[offset] != 0);
/* Offset is just in front of the last string. */
/* Print the string. */
s_printf ("%d: ", record);
int pos = offset + 1;
if (pos == sizeof (buffer->buffer))
pos = 0;
do
{
s_putchar (buffer->buffer[pos ++]);
if (pos == sizeof (buffer->buffer))
pos = 0;
}
while (buffer->buffer[pos] != 0);
s_putchar ('\n');
if (record == count)
break;
record ++;
}
while (processed < buffer->written);
if (! buffer->nolock)
ss_mutex_unlock (&buffer->lock);
}
#define trace_buffer_dump(buffer, count) \
trace_buffer_dump (__FUNCTION__, __LINE__, buffer, count)
#endif /* _HURD_TRACE_H */
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